/* nag_opt_handle_set_nlnls (e04rmc) Example Program.
 *
 * Copyright 2019 Numerical Algorithms Group.
 *
 * Mark 27.0, 2019.
 */

#include <stdio.h>
#include <nag.h>
#include <assert.h>

#ifdef __cplusplus
extern "C"
{
#endif
static void NAG_CALL objfun(Integer nvar, const double x[],
                            Integer nres, double rx[],
                            Integer *inform, Nag_Comm *comm);
#ifdef __cplusplus
}
#endif

int main(void)
{
  int          nvar, nres, isparse, nnzrd;
  Integer      icolrd[] = {1,2,3,1,2,3}, irowrd[] = {1,2,1,2,1,2};
  double       x[] = { 2.0, 2.0 };
  double       rinfo[100], stats[100];
  double       *rx;
  void         *handle;
  int exit_status = 0;

  /* Nag Types */
  Nag_Comm     comm;
  NagError     fail;

  printf("nag_opt_handle_set_nlnls (e04rmc) Example Program Results\n\n");
  fflush(stdout);
  
  /* Fill the problem data structure */
  nvar = 2;
  nres = 3;

  /* nag_opt_handle_init (e04rac).
   * Initialize the handle
   */
  nag_opt_handle_init(&handle, nvar, NAGERR_DEFAULT);

  /* nag_opt_handle_set_nlnls (e04rmc)
   * Define residuals structure,
   */
  isparse = 1;
  nnzrd = 6;
  nag_opt_handle_set_nlnls(handle, nres, isparse, nnzrd, irowrd, icolrd,
                           NAGERR_DEFAULT);

  /* nag_opt_handle_opt_set (e04zmc)
   * Set options
   */
  /* Relax the main convergence criteria a bit */
  nag_opt_handle_opt_set(handle, "DFLS Trust Region Tolerance = 1.0e-3",
                         NAGERR_DEFAULT);
  /* Deactivate the slow convergence detection */
  nag_opt_handle_opt_set(handle, "DFLS Maximum slow steps = 0",
                         NAGERR_DEFAULT);
  /* Turn off option printing */
  nag_opt_handle_opt_set(handle, "Print Options = NO", NAGERR_DEFAULT);
  /* Print the solution */
  nag_opt_handle_opt_set(handle, "Print Solution = YES", NAGERR_DEFAULT);
  /* Deactivate iteration log */
  nag_opt_handle_opt_set(handle, "Print Level = 1", NAGERR_DEFAULT);

  /* nag_opt_handle_solve_dfls (e04ffc)
   * Call the solver
   */
  rx = NAG_ALLOC(nres, double); assert(rx);
  INIT_FAIL(fail);
  nag_opt_handle_solve_dfls(handle, objfun, NULL, nvar, x, nres, rx,
                                 rinfo, stats, &comm, &fail);
  if (fail.code != NE_NOERROR){
    printf("Error from nag_opt_handle_solve_dfls (e04ffc).\n%s\n",
           fail.message);
    exit_status = 1;
  }

  /* Clean data */
  if (handle)
    /* nag_opt_handle_free (e04rzc).
     * Destroy the problem handle and deallocate all the memory used 
     */
    nag_opt_handle_free(&handle, NAGERR_DEFAULT);
  if (rx)
    NAG_FREE(rx);

  return exit_status;
}

static void NAG_CALL objfun(Integer nvar, const double x[],
                            Integer nres, double rx[],
                            Integer *inform, Nag_Comm *comm)
{
  /* Interrupt the solver if the dimensions does not correspond to the
   * problem
   */
  if (nvar != 2 || nres != 3)
    {
      *inform = -1;
      return;
    }

  rx[0] = x[0] + x[1] - 1.1;
  rx[1] = 2.0*x[0] + x[1] - 1.9;  
  rx[2] = 3.0*x[0] + x[1] - 3.0;
}